There are many applications in the industrial arts which require that various kinds of material be pulverized to a high degree of fineness. For example, the production of paint pigments and ceramic materials requires the particles to be on the order of 10 microns or smaller in diameter, i.e., in the ultrafine range.
Various methods and apparatus for pulverizing substances have been proposed in the past, including crushing, stamping, grinding, and forcing the substance against a metallic disk by means of a powerful current of air. These devices have proven to be inefficient and expensive, because of the rapid wear and destruction of the working parts of the apparatus.
The most effective of these methods and apparatus have been pulverizers of the type in which material in the form of large granules is thrown against a plate or wall and broken up by impact, and pulverizers in which the particles are thrown toward each other by two or more converging streams. These impact pulverizers are, however, subject to the difficulties that the plate wears out rapidly, that often the plate material becomes undesirably entrained with the material being pulverized, and that the pulverized material is often undesirably coarse for many desired uses.
One difficulty with conventional impact pulverizers is that the conventional jets or injectors have suffered from undue turbulence and less effective impact of the solid particles, which tends to increase wear and reduce the efficiency of the grinding operation to an unwarranted and undesired extent. The jets or nozzles within the pulverizers quickly become unduly and rapidly worn, often wearing eccentrically. This results in shortened periods of operation and relatively high repair or replacement costs. In addition, the construction of these pulverizers is such that replacement of the worn part often necessitates replacement of the entire assembly. In many pulverizers, it is also difficult to disassemble the device in order to inspect or repair a worn part.
The present invention addresses these and many other problems associated with currently available pulverizers.